Polyolefins stabilized with amine salts of phosphinodithioic acids

ABSTRACT

POLY-A-OLEFIN COMPOSITIONS HAVING IMPROVED LIGHT STABILITY. THE COMPOSITIONS COMPRISE AN A-OLEFIN POLYMER FORMED BY THE POLYMERIZATION OF AN A-MONO-OLEFINIC ALIPHATIC HYDROCARBON HAVING FROM 2 TO 10 CARBON ATOMS AND A STABILIZING QUANTITY OF A NOVEL ORGANOPHOSPHORUS AMINE SALT OF THE FORMULA:   R1-P(=S)(-R)-S- HR2(+)   WHEREIN R AND R1 ARE SELECTED FROM THE GROUP CONSISTING OF ALKYL, ALKOXY, ARYL, ARYLOXY AND ARALKYL; AND R2 IS AN AMINE SELECTED FROM THE GROUP CONSISTING OF SECONDARY AND TERTIARY HETEROCYCLIC AMINES.

United States Patent POLYOLEFINS STABILIZED WITH AMINE SALTS 0F PHOSPHINODITHIOIC ACIDS Stanley B. Mirviss, Stamford, Conn., and Melvin M. Schlechter, New Hyde Park, N.Y., assignors to Staulfer Chemical Company, New York, NY.

No Drawing. Original application Jan. 3, 1966, Ser. No. 517,950. Divided and this application Dec. 5, 1967, Ser. No. 708,459

Int. Cl. C08f 45/60 US. Cl. 26045.8 4 Claims ABSTRACT OF THE DISCLOSURE lPoly-u-olefin compositions having improved light stability. The compositions comprise an u-olefin polymer formed by the polymerization of an OL-Il'lOl'lO-OlC'fil'llC aliphatic hydrocarbon having from 2 to 10 carbon atoms and a stabilizing quantity of a novel organophosphorus amine salt of the formula:

wherein -R and R are selected from the group consisting of alkyl, alkoxy, aryl, aryloxy and aralkyl; and R is an amine selected from the group consisting of secondary and tertiary heterocyclic amines.

This application is a division of application No. 517,- 950, cfiled January 3, 1966, now abandoned.

This invention relates to novel organophosphorus amine salts. More particularly, this invention is concerned with novel heterocyclic amine salts of aromatic and aliphatic phosphinophosphonoand phosphorodithioic acids which are useful as light (ultra-violet) stabilizers for poly-alpha-olefin compositions.

It is known that plastic and polymeric materials generally undergo degradation in the presence of light and/ or heat. Especially sensitive to these agencies are some of the synthetic resins such as polyethylene, polypropylene and the like. In order to increase the life of plastics and polymers, it has become the practice to incorporate therein certain substances, usually referred to as ultra-violet absorbers which are capable of absorbing the incident actinic radiation, thereby protecting the plastic substrate from deterioration.

We have now discovered that certain heterocyclic amine salts are effective in protecting poly-alpha-olefins against the deleterious effects of light, and the provision of such compounds constitutes the primary purpose and object of this invention.

Another object of the invention is to provide polyalpha-oleifin compositions stabilized with the abovenamed compounds.

Other objects will be apparent from the detailed description which follows.

The novel compounds of the invention may be represented by the general formula wherein R and R are selected from the group consisting of alkyl, alkoxy, aryl, aryloxy and aralkyl; and R is an amine selected from the group consisting of secondary and tertiary heterocyclic amines. Representative examples would include pyridine, thiazine, morpholine, oxazine, piperazine, pyridazine, pyrimidine, pyrazine and the like.

3,574,163 Patented Apr. 6, 1971 The alkyl and alkoxy substituents may have from 1 to 20 carbon atoms.

The novel compounds of the invention are prepared by reacting an aromatic or aliphatic phospinodithioic or phosphorodithioic acid with a secondary or tertiary heterocyclic amine. An inert organic solvent such as benzene, toluene, acetone and the like is preferred but none is required.

We have discovered that generally excellent results are achieved when the starting materials are reacted at room temperature but the temperature range is not critical. Temperatures as low as 0 C. and as high as 200 C. may be maintained and generally the upper limit is the boiling point of the solvent.

Stoichiometric quantities of reactants are used and the reaction goes rapidly to completion. The crystalline precipitate formed is dried to produce a product having a yield in excess of The following examples which are illustrative of the invention should not be construed as limiting examples, for variations and modifications thereof will be apparent to one having ordinary skill in this art.

PREPARATION OF THE COMPOUNDS Example 1.-Pyridine salt of diphenylphosphinodithioic acid Example 2.-Morpholine salt of diphenylphosphinodithioic acid \IILS mo om H2C\/Hz having an analysis of 18.5% S and 4.30 N, as compared to 19.0% S and 4.2% N, theoretical, and a melting point of 213220 C.

Example 3.Piperazine salt of diphenylphosphinodithioic acid having an analysis of 18.4% S and 8.3% N, as compared to 18.8% S and 8.3% N, theoretical, and a melting point of 220-228" C.

Example 4.Pyridine salt of 0,0-diphenylphos- Dry blends consisting of 0.5% by weight of each of phorodithioic acid the compounds of Examples 1 to 6 and 50 grams of iso- NH tactic polypropylene were subjected to compression molds ing in the usual manner at a temperature of 400 F. for il 5 six minutes at 2000 p.s.i. The blended polymers were HC OH compression molded or extruded into 25 ml. sheets and 6 E thereafter cut into square samples measuring 2 inches on the side. A like sample containing no stabilizer was also prepared and tested. The samples were then exposed in 10 a Xenon Arc Weatherometer operating at 6000 watts. The

having an analysis of 17.1% S as compared to a 17.7% S, theoretical, and a melting point of 9395 C.

Example 5.Pyridine salt of 0,0-di(tridecyl) water cycle was adjusted whereby each sample was subphosphorodithioic acid jected to 18 minutes of water spray and 102 minutes of CHKCHZMOHZO s NH dry exposure for each of two hours of exposure. Exposure damage to the samples of polypropylene was as- :l sessed with respect to change of structural strength.

CH1(CH2)11CH2O HO OH After a period of exposure in excess of 600 hours, none fl of the test sheets of polypropylene showed signs of brittleness when flexed at an angle of 180 and three of the test sheets showed no signs of brittleness when flexed 20 after 800 hours of exposure. A blank specimen of unhaving an analysis of 11.1% S as compared to 11.1% S, theoretical, and a melting point of 43-45 C.

Example 6.Pyridine salt of 0,0-dioctadecyl stabilized polypropylene which was exposed concurrently phosphorodithioic acid With the stabilized product failed the flexure test after 0113mm) l6CHZO S NH 250 to 300 hours exposure time.

I The polypropylene resin as used in the above-described I: z example is an unstabilized general purpose, high molec- CHa( 2)|eC 20 H H ular weight polypropylene of the isotactic or crystalline fi type. Typically, it has a melt index of 4 at 230 C. and

The following compounds are prepared in accordance a i s gg gf of Wlth the procedure of Examp 1e 1. A solid poly-alpha-olefin composition having im- Example 7.-Pyridine salt of benzyl phenylproved stability toward light degradation which comphosphinodithioic acid prises an alpha-olefin polymer formed by the polymeri- NH zation of an alpha-mono-olefinic aliphatic hydrocarbon having from 2 to 10 carbon atoms and a stabilizing quan- I my of a novel organophosphorus amlne salt of the II H 0 0H 0 H2 formula OH R S Example 8.-Pyridine salt of O-methyl p- I S] [H 1+ tolylphosphonodithloic ac1d R2 NH HaC fi wherein R and R are selected from the group consisting PS g of alkyl of from 1 to 20 carbon atoms, phenyl and benzyl oHao/ and R is a secondary or tertiary heterocyclic amine se- CH lected from the group consisting of pyridine, thiazine, Example 9.-Pyridine salt of O-ethyl naphthyl- OXaZiIle, p p pyrimidine, PY and pyridalineh h nodjthioi id 2. The composition of claim 1 wherein the polyolefin is polypropylene and the novel organophosphorus amine NH salt is the pyridine salt of diphenylphosphinodithioic acid. 3. The composition of claim 1 wherein the polyolefin fi Is polypropylene and the novel organophosphorus oxa- P-S zine salt is the morpholine salt of diphenylphosphinodithioic acid. 021350 CH 4. The composition of claim 1 wherein the polyolefin The ultra-violet stabilizer compounds contemplated by is polypropylene and the novel organophosphorus amine the invention may be blended or incorporated into the salt is the piperazine salt of diphenylphosphinodithioic poly-alpha-olefin compositions by any of the conventional acid. methods commonly used for mixing such materials with References Cited resinsand plastics. For example, milling on heated r0lls, UNITED STATES PATENTS deposition from solvents and dry blending are applicable well known techniques 2,063,629 12/1936 Salzberg et al. 260925 In order to prepare poly-alpha-olefin compositions 2,930,730 3/1960 Scott 26O 925 which are resistant to prolonged exposure to sunlight and 3,041,311 6/1962 Baum} 26045-75 the elements, it is preferred that the concentration of the $124,556 3/1964 Mernfield et 26045-7 novel compounds be maintained in the range of 0.01 to 5 330L447 8/1965 Y P 7 260-925 about 5.0% based on the weight of the polymer. 3,293,208 12/1966 Mlhoms at 26045-75 Although the molecular weight of the poly-alpha-ole- 3,356,773 12/1967 Bacon 260'978 fins varies over wide limits, the compounds of the inven- 3424715 1/1969 Kopackl ct 260 45-9 tion are not restricted to any particular molecular weight 3,422,058 1/1969 Grew 260-458 range. Poly-alpha-olefin ranging in molecular Weight from about 15,000 to about 400,000, however, are af- DONALD CZAJA Pnmary Exammer forded particularly excellent protection, R. A. WHITE, Assistant Examiner 

